AB0181 PAIN SENSITIZATION IN ADOLESCENCE: MUSCULOSKELETAL PAIN HISTORY AND EXPERIMENTAL PAIN RESPONSES IN A POPULATION-BASED COHORT STUDY
Authors: R. Lucas, M. Brandão, F. Fernandes, S. Holden, M. Talih, T. Graven-Nielsen
Journal: Annals of the Rheumatic Diseases (2023)

<h3>Background</h3> Prolonged exposure to pain may induce sensitisation through neuroplastic processes, resulting in gain/loss of function and alteration of signal processing, and probably playing an important role in the experience and chronification of pain. Quantitative sensory testing (QST) assesses responses to standardised stimuli, allowing for an estimation of the effects of health conditions on somatosensory function [1]. Sensitized pain mechanisms are often reported in adults with musculoskeletal pain conditions, but population-based pediatric studies are lacking. <h3>Objectives</h3> To investigate the association between reported musculoskeletal pain history (based on complementary criteria) and pain sensitisation measures at age 13 years in a population-based cohort. We hypothesised that adolescents reporting more adverse musculoskeletal pain experiences would have higher pain sensitivity, impaired anti-nociceptive and/or facilitated pro-nociceptive mechanisms. <h3>Methods</h3> We analyzed data from 1496 adolescents of the population-based Generation XXI birth cohort study in Porto, Portugal. Pain history was collected using the Luebeck Pain Questionnaire (self-reported at 13 years, parent-reported at 7 and 10 years). Musculoskeletal pain was considered present if reported in the back, neck, shoulders, upper/lower limbs, hips, or widespread musculoskeletal. Three case definitions for adverse musculoskeletal pain history were used: 1) chronic (3+ months) musculoskeletal pain at age 13; 2) musculoskeletal pain with an impact on daily living (school and/or hobbies) at age 13; and 3) musculoskeletal pain at age 13 together with previous musculoskeletal pain reports at ages 7 and/or 10 (reported in previous data collection waves). Lower limb cuff pressure algometry was conducted at age 13 using a computerized system coupled with a visual analogue scale for pain intensity rating. We extracted pain sensitivity (pain detection and tolerance thresholds), conditioned pain modulation (CPM, changes in thresholds in the presence of a distant painful conditioning) and temporal pain summation (TSP, changes in pain intensity to ten phasic painful cuff stimulations). Non-parametric tests were used to compare QST parameter distributions. <h3>Results</h3> Adolescents with musculoskeletal pain at age 13 who had a history of musculoskeletal pain at ages 7 and/or 10 had lower pain tolerance threshold compared to the remaining sample (mean 40.2 vs. 49.0 kPa, p=0.020) and lower pain detection threshold point estimate (14.5 vs. 18.2, p=0.072). Slightly lowered pain tolerance was also found in adolescents with musculoskeletal pain with an impact on daily living at age 13 (42.4 vs. 49.0, p=0.091). No differences were found for pain sensitivity measures according to the presence of pain lasting 3+ months at age 13. No differences were found for CPM-effects and TSP-effects according to pain history regardless of the case definition used. <h3>Conclusion</h3> Repeated musculoskeletal pain up to age 13 years may contribute to lower pain tolerance in the general adolescent population. This does not seem to be the case when reported pain experiences are recent or when the outcomes are temporal pain summation or conditioned pain modulation. In this community-based sample the vast majority showed no sign of altered central pain processing but a small fraction with longer pain experiences may reveal some pain sensitization at 13 years of age. <h3>Reference</h3> [1]Holden, S., Straszek, C. L., Rathleff, M. S., Petersen, K. K., Roos, E. M., &amp; Graven-Nielsen, T. (2018). Young females with long-standing patellofemoral pain display impaired conditioned pain modulation, increased temporal summation of pain, and widespread hyperalgesia. Pain, 159(12), 2530-2537. <h3>Acknowledgements</h3> This work was supported by FOREUM - Foundation for Research in Rheumatology (Career Research Grant). Cohort funded by EPIUnit at ISPUP, Universidade do Porto (UID/DTP/04750/2019), Regional Department of the Portuguese Ministry of Health and Calouste Gulbenkian Foundation. MT was funded by the ERDF, through the North Regional Operational Program in the framework of the project HEALTH-UNORTE (NORTE-01-0145-FEDER-000039). Nocitech is partly owned by Aalborg University. <h3>Disclosure of Interests</h3> None Declared.